Inspection Procedure 11

Inspection procedure 11: When the engine is hot, it stalls at idle (die out)

COMMENT
- In cases such as the above, the ignition system, air/fuel mixture or compression pressure may be faulty. In addition, if the engine suddenly stalls, the cause may also be a connector damage.

TROUBLESHOOTING HINTS (The most likely causes for this case:)
- Fuel pump system failed.
- Ignition system failed.
- Poor compression.
- Improper operation of the PCV valve.
- Vacuum leak.
- Dirtiness around throttle valve.
- ECM failed.

DIAGNOSIS

Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991910: Main Harness A

STEP 1. Using scan tool MB991958, read the diagnostic trouble code (DTC).






CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.

1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Read the DTC.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is any DTC set?

YES : Refer to, Diagnostic Trouble Code Chart. Diagnostic Trouble Code Descriptions

NO : Go to Step 2.

STEP 2. Using scan tool MB991958, check actuator test.

1. Turn the ignition switch to the "ON" position.

2. Check the following item in the actuator test. Refer to Actuator Test Reference Table Actuator Test Reference Table.
a. Item 1: Injectors

3. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Are they operating properly?

YES : Go to Step 3.

NO : Repair or replace it. Then confirm that the malfunction symptom is eliminated.

STEP 3. Using scan tool MB991958, check data list.

1. Turn the ignition switch to the "ON" position.

2. Check the following items in the data list. Refer to Data List Reference Table Datal List Reference Table.
a. Item 5: Intake Air Temperature Sensor
b. Item 6: Engine Coolant Temperature Sensor
c. Item 13: Throttle Position Sensor (main)

3. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Are they operating properly?

YES : Go to Step 4.

NO : Repair or replace it. Then confirm that the malfunction symptom is eliminated.

STEP 4. Inspection of throttle body (throttle valve area) for dirtiness.

Q: Is the throttle valve area dirty?

YES : Refer to On-vehicle Service - Throttle Body (Throttle Valve Area) Cleaning.

NO : Go to Step 5.

STEP 5. Check the fuel pressure.

Refer to Fuel Pressure Test Testing and Inspection.

Q: Is the fuel pressure normal?

YES : Go to Step 6.

NO : Repair or replace it. Then confirm that the malfunction symptom is eliminated.

STEP 6. Check the ignition timing.

Refer to On-vehicle Service - Ignition Timing Check. Testing and Inspection

Q: Is the ignition timing normal?

YES : Go to Step 7.

NO : Check for installed conditions of the timing chain. Then confirm that the malfunction symptom is eliminated.

STEP 7. Check the spark plugs.

Refer to On-vehicle Service - Spark Plug Check and Cleaning. Testing and Inspection

Q: Are there any abnormalities?

YES : Replace the spark plug. Then confirm that the malfunction symptom is eliminated.

NO : Go to Step 8.

STEP 8. Check the ignition coil.

Refer to On-vehicle Service - Ignition Coil Check. Ignition Coil Check

Q: Are there any abnormalities?

YES : Replace the ignition coil. Then confirm that the malfunction symptom is eliminated.

NO : Go to Step 9.

STEP 9. Check the compression pressure.

Refer to On-vehicle Service - Compression Pressure Check. Compression Check

Q: Is the compression pressure normal?

YES : Go to Step 10.

NO : Repair it. Then confirm that the malfunction symptom is eliminated.

STEP 10. Check the positive crankcase ventilation system.

Refer to Positive Crankcase Ventilation System Check. System Check

Q: Is the positive crankcase ventilation system normal?

YES : Go to Step 11.

NO : Repair it. Then confirm that the malfunction symptom is eliminated.

STEP 11. Engine stall reproduction test.

Q: Is it easy to reproduce the engine stall?

YES : Check the following items, and repair or replace the defective items.
a. Vacuum leak.
b. Check if fuel is contaminated.
c. Check if the injectors are clogged.
d. Check if the foreign materials (water, kerosene, etc.) got into fuel.

Then confirm that the malfunction symptom is eliminated.

NO : Check if the following signals change suddenly by wiggling the circuit harness and connectors.
a. Crankshaft position sensor signal.
b. Mass airflow sensor signal.
c. Injector drive signal.
d. Primary and secondary ignition signal.
e. Fuel pump drive signal.
f. ECM power supply voltage.

Then confirm that the malfunction symptom is eliminated.